Method in covering building element surfaces with sheet metal



p 1961 w. WREDENFORS 3,000,093

METHOD IN COVERING BUILDING ELEMENT SURFACES WITH SHEET METAL Filed April 2, 1958 I NVENTOR:

WaHer Wredenfors United States Patent 3,000,093 METHOD 1N COVERING BUILDING ELEMENT SURFACES WITH SHEET METAL Walter Wredenfors, Mockfjard, Sweden, assignor to Aktiebolaget Bostodsforskniug, Stockholm, Sweden, :1

Swedish joint-stock company Filed Apr. 2, 1958, Ser. No. 725,914 3 Claims. (Cl. 29505) invention relates to a method of covering the surface of a panel, board or similar rigid building element with sheet metal, preferably sheet aluminum, for the purpose of protecting the building element surface and making it highly weather resistant, so that it may be used externally of a building.

The main object of the invention is to simplify the process' of covering the surface with a firmly secured sheet metal, so that this process may be readily mechanized and thus economically utilized in the productionof so called prefabricated building elements which for their protection require a continuous sheet metal covering Without perforations at the joints and avoiding the use of separate fastening means whichpierce through the sheet metal covering. r

According to the present invention the surface of the panel or the like to be covered, which is commonly but not necessarily of a wooden material, is in a manner known per se provided with a plurality of undercut, preferably parallel grooves having a substantially dovetailshaped cross section, while the sheet metal cover to be applied to the surface is formed with corresponding channel-shaped ridges or folds having substantially parallel side portions and a depth greater than that of the grooves. Thereafter, the sheet metal cover is placed upon the grooved element surface with its ridges received in the grooves thereof, and the ridges of the sheet metal cover are deformed to form linings tightly abutting at least the undercut sides of the related dovetail-shaped grooves.

The method according to the invention is mainly characterized by the fact that the channel-shaped ridges or folds of the sheet metal cover are originally formed with a concave, preferably rounded bottom portion and with a maximum depth which exceeds the maximum depth of the dovetail-shaped grooves in the surface to be covered, and that the sheet metal cover when being attached to the surface is subjected to a pressure directed towards the surface to be covered and acting at least on the side portions of the channel-shaped ridges so that each ridge as a result of its pressing down into the related, dovetailshaped groove is deformed and widened to substantially follow the sectional contour of the dovetail-shaped groove.

The invention may be carried out in many difierent ways and in order to ensure a clear understanding of the invention two illustrative embodiments thereof are hereinafter described in detail with reference to the attached drawings, wherein:

FIG. 1 shows a cross section of a first panel with a sheet metal cover partly secured thereto and partly ready to be secured, while FIG. 2 in a similar manner shows a cross section of a second panel with a sheet metal cover partly secured thereto and partly ready to be secured to the panel.

- It is to be observed that the above views of the drawing are diagrammatic only and are only intended to illustrate the sheet metal fastening principle without detailing the means or devices necessary for performing the work in practice, since any technically skilled man will readily understand how these means may be constructed.

Referring to FIG. 1, it will be seen that the panel or other building element 1 to be covered is formed with dovetail-shaped grooves 2 in its surface which is to be protected by a sheet metal cover 3 having channel-shaped Patented Sept. 19, 1961 ridges or folds 4 formed therein. A small space 5 is provided between the sheet metal cover 3 and the areas of the element surface intermediate the grooves 2 for the purpose of allowing contraction of the sheet metal in a transverse direction relative to the grooves 2. A pressing tool 6, such as for instance a press head or a roller, is provided for exerting a pressure on the sheet metal cover in order to lock the ridges 4 in the grooves 2.

In the embodiment of FIG. 1, the channel shaped ridges 4 of the sheet metal cover are preformed with parallel sides and a concave bottom while the dovetail shaped grooves 2 in the panel 1 are formed with a slightly concave bottom having a much greater radius of curvature. The maximum depth of these preformed ridges 4 somewhat exceeds the maximum depth of the grooves 2 so that the side portions of the channel shaped ridges protrude a small distance over the upper edges of the dovetail shaped grooves as is shown in the left-hand part of FIG. 1. Thus, each ridge 4 is so shaped and dimensioned that, when a pressure acting perpendicularly to the surface of the panel 1 is exerted by means of a pressing tool 6 on the raised side portions of the channel shaped ridge, the ridge is pressed down into the groove 2 while at the same time its bottom portion is spread out or flattened and its side portions are spread apart or made to diverge downwardly. As a result the ridge is deformed to rather accurately follow or line the cross sectional contour of the groove 2, as shown in the righthand part of FIG. 1.

The method illustrated in FIG. 2 is generally similar to that described above with reference to FIG. 1 and, in FIG. 2, the various parts are identified by the same reference numerals, but the latter are primed. In accordance with the method of FIG. 2, each channel shaped ridge '4 of the sheet metal cover 3' is formed with a V-shaped bottom portion. As a result when the ridge 4' is pressed into the groove '2, the V-shaped bottom portion of the ridge is flattened against the flat bottom of the groove to spread apart the sides of the ridge for interlocking engagement with the dovetail groove. In this case the pressing tool 6 also applies a pressure against the upstanding side portions of the channel-shaped ridge and, consequently, in both illustrated embodiments, it is unnecessary to insert any pressing or deforming tool into the grooves of the element.

It will be readily understood that the pressing tool may be either a vertically reciprocating press head covering the entire surface of the panel or only a part thereof, or a pressing roller preferably extending across the entire width of the panel to be covered, and being advanced over the element surface to successively press down the sheet metal cover and thereby to cause the ridges of the latter to be deformed and anchored in the grooves of the building element surface. In either case it is completely unimportant where the grooves are located on the element surface and consequently the mutual distance between the grooves may be varied at will without any changes being necessary in the pressure applicating device. On the other hand it is of course always necessary to make sure that the ridges of the sheet metal cover are located to properly fit into the corresponding grooves of the element surface.

It will be readily understood that the fact that the sheet metal cover is anchored by deformation in the grooves of the building element surface does not preelude the additional bonding of the sheet metal to the underlying surface by a suitable layer of adhesive or cement such as asphalt, rubber cement or the like. Such a preferably elastically hardening filling between the sheet metal cover and the element surface also serves to stabilize the sheet metal, so that the latter is prevented from causing noise and rattle by flexing.

I claim:

1. A method of covering a surface of a building element with a continuous, imperforate sheet metal cover, comprising the steps of forming said surface to be covered with a plurality of parallelly spaced apart undercut grooves of substantially dove-tail shaped cross-section, torming the sheet metal cover with corresponding channelshaped ridges which are parallelly spaced apart by dis- 'tances slightly larger thanthe distances bet-ween said grooves and each having substantially parallel side portions and a concave bottom portion shaped to contact the bottom of the groove only at the center of the latter, with the depth of the ridge to the center of said concave bottom portion being substantially greater than the depth of the related groove in the building element, placing the formed sheet metal cover against said surface of the building element with said ridges registering with, and entering into said grooves, and exerting a pressure only against the portions of said cover between said ridges in the direction toward, and substantially perpendicular to said surface to be covered and acting at least against said side portions of the ridgw so that each ridge is pressed into the related groove and has its bottom portion flattened against the bottom of the groove to cause said side portions of the ridge to plastically expand outwardly into the undercut portions of the groove for close adherence to the under cut sides of the latter, while said 4 portions of the cover between said ridges are bowed outwardly away from said surface thereby to permit expansion and contraction of the sheet metal cover relative to the building element.

2. A method as in claim 1; wherein said bottom portion of each ridge is arcuately concave and the bottom of the related groove has an arcuate cross-section with a radius of curvature much greater than that of said arcuately concave bottom portions of the ridge.

3. A method as in claim 1; wherein said bottom portion of each ridge is V-shaped in cross-section and the bottom of the related groove is flat.

References Cited in the file of this patent UNITED STATES PATENTS 2,050,993 Bush Aug. 11, 1936 2,164,414 Long July 4, 1939 2,258,858 Meadowcrofit Oct. 14, 1941 2,277,108 Jackson Mar. 24, 1942 2,313,228 Domonkos Mar. 9, 1943 2,391,997 Noble Jan. 1, 1946 2,453,503 Emmons Nov. 9, 1948 2,863,185 Riedi Dec. 9, 1958 FOREIGN PATENTS 764,771 France Mar. 12, 1934 524,344 Belgium Dec. 15,1953

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,000,093 September 19, 1961 Walter Wredenfors It is hereby certified that error appears in the 'above numbered pat-- ent requiring correction and that the said Letters Patent should read as corrected below.

In the grant, lines 2 and 12, and in the-heading tothe printed specification, line Q15, name of assignee, for "Aktieboj get Bostodsforskniny' read Aktieblaget Bostadsforskning Signed and sealed this 12th vd'ay of June 1962'.

(SEAL) Attest:

ERNEST w. SWIDER V DAVID LADD Attesfing Officer a Commissioner of Patents 

